The invention pertains to a method for producing a contiguous ice body in a ground freezing process.
In this context, brine cooling is an established and safe ground freezing and foundation soil securing method, which is by all means capable of competing with other methods such as, e.g., concrete injection. However, tests have shown that brine cooling reaches its limits at groundwater velocities above 2 m/day, i.e., a contiguous, monolithic ice body (also referred to as frost body), which encloses all cooling lances, can usually no longer be produced. Among other things, one reason for this is an occurring nozzle effect. The ice body growing around the cooling lances restricts the flow cross sections for the groundwater or flow medium. This in turn increases the flow velocity and the heat flow density at the edge of the ice body. A stationary state, in which the ice body no longer grows, may be reached before a cohesive ice body has formed.
Based on these circumstances, the invention aims to make available a method that makes it possible to produce a contiguous ice body.
This objective is attained by means of a method for producing a contiguous ice body in a around region, wherein first cooling lances are inserted into the around region, in which the contiguous ice body should be produced in the presence of a flow of a fluidic flow medium, particularly in the form of groundwater, flowing through the ground region, wherein a first refrigerant is introduced into the first cooling lances, and wherein at least one second cooling lance is furthermore inserted into the ground region on a side of the first cooling lances facing the flow and a second refrigerant, which has a temperature that is lower than the temperature of the first refrigerant, is introduced into the at least one second cooling lance in order to promote the formation of a contiguous ice body that encloses all cooling lances.